Electric heater for a seat assembly

ABSTRACT

A heating element that can be incorporated into a molded foam article closely adjacent to the outer cover sheet without showing any evidence that a heating element is encapsulated within the foam portion of the article and provides essentially the same relatively softness and “feel” that would be obtained if the heating element was not part of the article.

TECHNICAL FIELD

[0001] This invention relates to vehicle seats and more particularlyconcerns an electric heating element for a vehicle seat in which thetrim cover is integrally affixed to a foam cushion member.

BACKGROUND OF THE INVENTION

[0002] It is well known to have a built-in heating element for providingheat to the body of the occupant of the driver seat and/or the passengerseat of a motor vehicle. The heat is provided by electric currentsupplied through a conductor having suitable resistivity that ensuresthe desired amount of heat from the conductor. The conductor, in theform of a resistance wire, is located on a layer of textile or a plasticmaterial to provide a carrier in the form of a planar or flat sheet. Theresistance wire is fixed in position on the carrier by stitching meansor by an adhesive and, afterwards, positioned between various layers ofmaterial to form the heating element which then can be incorporated intoa seat. In this regard, the heating element can be sandwiched between atop cover member of leather, fabric or plastic material and the foamrubber core portion or padding of the seat.

[0003] Seats provided for vehicles used for material handling,earthmoving, or lawn cutting are normally fabricated utilizing anin-mold forming process to reduce the cost of the seat. This type ofprocess provides a seat having a core made of a plastic foam, such aspolyurethane foam, that is bonded to an outer decorative cover sheet orskin during the molding process. In the practice of such process, aproperly shaped mold cavity is lined with a thin plastic or fabric skinafter which liquid polyurethane is poured onto the skin to form anintegral seat cushion or seat back. Various attempts have been made toprovide a relatively inexpensive seat of this type that would have aheating element incorporated between the skin of the article and thefoam layer. In most cases, such attempts have resulted in theconfiguration of the heating element and/or the conductor being outlinedin the cover sheet and, therefore, not acceptable from an aestheticstandpoint. Obviously, if the heating element could be spaced from theskin a certain distance, maintained in such position, and completelyencapsulated in the foam during the molding operation, the “reading” ofor outline of the heating element would not be visible to the observer.

[0004] There has also been the problem in providing a comfortable “feel”to the buttocks of a seat occupant when seated in a seat assembly havinga heating element as a part of the seat structure. Inasmuch as theheating element needs to be positioned relatively close to the outerskin of a seat member and becomes an integral part of the foamstructure, it stands to reason that the heating element should bedesigned and constructed so that it does not take away from the softnessand comfort of the seat. In other words, not only should the heatingelement within the seat not be detectable from an appearance standpointbut, in addition, the heating element should not cause the seat toprovide any substantially less comfort when occupied than would beattainable if the heating element was not a part of the seat.

SUMMARY OF THE INVENTION

[0005] Accordingly, one object of the present invention is to provide anew and improved heating element that can be incorporated into a moldedfoam article closely adjacent to the outer cover sheet without showingany evidence that a heating element is encapsulated within the foamportion of the article and provides essentially the same relativelysoftness and “feel” that would be obtained if the heating element wasnot part of the article.

[0006] Another object of the present invention is to provide a new andimproved heating element which can be positioned relatively close to theouter skin of a seat member and permit the occupant of the seat memberto have a comfortable and relatively soft seating area without detectingany hardness or the “feel” of the heating element through his/herbuttocks when sitting in the seat member.

[0007] A further object of the present invention is to provide a new andimproved heating element for a seat member formed as a molded foamarticle that includes a porous carrier member having resistance wiresattached to one side thereof and that serves as a spacer for preventingthe heating element and/or the resistance wires from being outlined orin the outer skin of the seat member.

[0008] A still further object of the present invention is to provide anew and improved heating element for a seat member formed as a moldedfoam article that is held to the skin of the seat member in a fixedposition during the molding operation so as to insure that the heatingelement is completely embedded within the foam and is substantiallyuniformly spaced from the outer skin of the seat member.

[0009] A still further object of the present invention is to provide anew and improved method of incorporating a heating element within amolded foam seat member so that it is not evident that a heating elementis encapsulated within the article and the heating element is maintaineduniformly closely adjacent to the outer skin of the article so as toeffectively transfer heat to the occupant of the seat member and providea relatively soft “feel” to the buttocks of the occupant.

[0010] The above and other objects of the present invention are realizedin accordance with the present invention by providing a heating elementfor an in-place foam molded seat assembly having a seat cushion memberand a seat back member each of which has the foam core thereofintegrally formed with the outer cover sheet. More specifically and inthe preferred form, the heating element comprises a generallyrectangular carrier member having an open-cell reticulated plasticstructure provided with a pair of spaced substantially parallel planarsurfaces. An electric conductor in the form of a resistance wire issecured to one of the surfaces of the carrier member in a zig-zagpattern and in a plurality of spaced rows so as to cover substantiallythe entire area of the carrier member. In addition, in the preferredform, a double-faced adhesive tape incorporating a scrim as areinforcement member is provided on the other of the pair of surfaces ofthe carrier member. The tape is adapted to connect the carrier member tothe inner surface of the cover sheet so as to maintain the resistancewire spaced from and in a fixed position relative to the inner surfaceof the cover sheet during the molding of the seat member.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other objects and advantages of the present invention will beapparent from the following detailed description when taken with thedrawings in which:

[0012]FIG. 1 is a perspective view of a molded foam seat assembly inwhich the seat cushion member incorporates a heating element made inaccordance with the present invention;

[0013]FIG. 2 is an enlarged cross sectional view taken on line 2-2 ofFIG. 1 showing the heating element located with its resistance wiressubstantially uniformly spaced from the cover sheet of the seat cushionmember and completed embedded within the foam material thereof;

[0014]FIG. 3 is a perspective view of the heating element prior to beingincorporated into the cavity of a mold for forming the seat cushionmember seen in FIG. 1;

[0015]FIG. 4 is an enlarged plan view of a portion of the heatingelement seen in FIG. 3 showing the manner that the resistance wire issecured to the upper surface of the carrier member of the heatingelement;

[0016]FIG. 5 is a sectional view taken on line 5-5 of FIG. 4;

[0017]FIG. 6 is a perspective view of a mold having a lower mold portionand an upper mold portion used in forming the seat cushion of the seatassembly of FIG. 1 and shows the pre-formed cover sheet of the seatcushion member preparatory to its positioning within the cavity of thelower mold portion;

[0018]FIG. 7 shows the pre-formed cover sheet of the seat cushionlocated within the lower mold portion and also shows the heating elementof FIG. 3 located in the buttocks area of the cover sheet within thecavity of the lower mold portion prior to the pouring of a liquid foammaterial into the mold;

[0019]FIG. 8 shows the liquid foam material covering the heating elementprior to the closing of the mold after which the mold is closed and theliquid foam material is molded to form the seat cushion of FIGS. 1 and2; and

[0020]FIG. 9 is an enlargement of the portion circled and indicated bythe letter “A” and shows in detail the construction of the double facedadhesive tape applied to the lower surface of the carrier member of theheating element.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Referring to the drawings and more particularly to FIGS. 1 and 2thereof, a vehicle seat assembly 10 is shown comprising a seat cushionmember 12 and a seat back member 14. The seat cushion member 12 includesa heating element 16, made in accordance with the invention, that islocated in the buttocks support portion 18 of the seat cushion member 12and serves to heat the buttocks of an occupant sitting in the seatassembly 10. As best seen in FIG. 2, the core portion 20 of the seatcushion member 12 is made of a foam material, such as polyurethane foam,which in this case, is shown securely bonded through the heating element16 to the inner surface 22 of an outer cover sheet 24. The outer coversheet 24 takes the form of a thin plastisol skin, such as vinylplastisol, vinyl drysol, butadiene styrene or other known foamimpermeable material. If desired, the cover sheet 24 can be a fabricmaterial having a plastic backing so as to render it impermeable to thefoam material which will ultimately constitute the core portion 20 ofthe seat cushion 12. As will be more fully described hereinafter, theseat cushion 12 is made in its entirety in a mold cavity which isconfigured so as to form the seat cushion 12 shown with a pair oflaterally spaced raised side sections 26 and 28 and a raised frontsection 30, all of which define the recessed buttocks support portion18.

[0022] As seen in FIG. 2, the heating element 16 is embedded in itsentirety within the foam core portion 20 of the seat cushion member 12in the area of the buttocks support portion 18. More specifically and asseen in FIGS. 3 and 4, the heating element 16 comprises a generallyrectangular carrier member 32 in the form of a net-like reticulated foamhaving a network of open cells throughout its entire flexible body. Thecarrier member 32, as seen in FIGS. 3 and 5, has a pair of spacedparallel surfaces, namely, an upper planar surface 34 and a lower planarsurface 36. The upper surface 34, as seen in FIGS. 3 and 4, serves tofixedly support an electric resistance wire 38 which has a pair of ends40 and 42, each of which is respectively connected by a connector 44 toconductors 46 and 48 located in an electric cable 50. The resistancewire 38 is arranged in a zig-zag pattern in three substantially parallelrows so as to cover most of the area of the upper surface 34 of thecarrier member 32. As best seen in FIG. 4, the straight section 52 ofeach of the loops of the resistance wire 38 forming the zig-zagarrangement is connected by a hot-melt adhesive to one or more webportions of the carrier member 32.

[0023] As seen in FIG. 3, a thermostat 56 is provided on the uppersurface 34 of the carrier member 32 at one side thereof midway of theadjacent row of the resistance wire 38 and serves to sense thetemperature of the heating element 16. The thermostat 56 controls thetime when the resistance wire 38 is energized so as to provide asubstantially uniform heat to the occupant of the seat assembly 10. Asin the case of the two ends 40 and 42 of the resistance wire 38, eachend of the two conductors leading to the thermostat 56 are connectedthrough a connector to one end of a pair of conductors located in theelectrical cable 50. Also, as in the case of the resistance wire 38, theconductors leading to the thermostat 56 are secured to the webs of thecarrier member 32 by a hot-melt adhesive 54. At this juncture, it shouldbe noted that the electric cable 50 connects electrically throughsuitable switch and control means with the electrical power of thevehicle so as to provide electricity to both the resistance wire 38 anthe thermostat 56 when it is desired by the occupant of the seatassembly 10.

[0024] As seen in FIG. 4, the webs along the entire lower surface 36 ofthe carrier member 32 are bonded to one face of a double-faced adhesivetransfer tape 58. The tape 58 is of the same rectangular shape as thatof the carrier member 32 and is coextensive with the lower surface 36thereof. As best seen in FIG. 9, the tape 58 has a layer of pressuresensitive adhesive 58′ coated on opposed sides of a scrim 58″ made of awoven synthetic fiber. A specially treated paper liner 59 covers theentire lower face of the tape 58 and is removable therefrom withoutdisturbing the adhesive adhering to the lower face of the tape 58. Aswill be more fully explained hereinafter, the liner 59 is removed toexpose the lower face of the tape 58 prior to the heating element 16being incorporated into the seat cushion 12. In addition and as willbecome more apparent as the description of the present inventionproceeds, the tape 58 serves as a connector for maintaining the carriermember 32 in a fixed position during the molding process used in makingthe seat cushion member 12.

[0025] As mentioned above, the heating element 16 described above and asseen in FIG. 2 is embedded within the foam core portion 20 of the seatcushion member 12 closely adjacent to the inner surface 22 of the coversheet 24. In practicing the process for obtaining this result, a twopiece mold 60, as seen in FIG. 6, is provided comprising an upper moldportion 62 and a lower mold portion 64. The lower mold portion 64 isformed with a cavity 66 which conforms in shape to the upper part, asseen in FIG. 1, of the seat cushion member 12 while the upper moldportion 62 is provided with a cavity 68 which conforms to the bottompart of the seat cushion member 12. The upper mold portion 62 ispivotally connected to the lower mold portion 64 and is adapted to pivotdownwardly onto the lower mold portion 64 so that the cavities 66 and 68of the upper and lower mold portions 62 and 64, respectively, registerwith each other.

[0026] Prior to closing the mold 60, a flat sheet 70 made of a vinylmaterial, such as described above, is initially pre-formed so as to havethe configuration of the seat cushion member 12. In this manner, thecover sheet 24 of the seat cushion member 12 is provided as an integralpart of the sheet 70. Pre-forming of materials of this type is wellknown to those skilled in the art of in-place molding of articles.Accordingly, a description of the pre-forming process for achieving theconfiguration of the cover sheet 24 in the sheet 70 shall not bedescribed in detail herein.

[0027] Once the sheet 70 is preformed as seen in FIG. 6, the sheet 70 ispositioned on the lower mold portion 64 with the cover sheet 24 locatedin the cavity 66, as seen in FIG. 7. The extremities of the sheet 70surrounding the cover sheet 24 are held in place by a generally squareopen frame member 74 made of metal that is secured to the body of thelower mold portion 64 by a plurality of clamps 76. After the sheet 70 isproperly located in the lower mold portion 64 and secured in place, theliner 59 is removed from the tape 58 by peeling the liner 59 off of thelower face of the tape 58. The heating element 16 is then placed in thearea of the buttocks support portion 18 with exposed side of theadhesive 58′ of the lower face of the tape 58 facing downwardly towardsthe inner surface 22 of the cover sheet 24. As a result, the exposedadhesive 58′ on the lower face of the tape 58 contacts the inner surface22 of the cover sheet 24 and adhesively secures the heating element 16in a fixed position relative to the cover sheet 24. In order to havegood adhesion between the tape 58 and the inner surface 22 of the coversheet 24, the entire heating element 16 should be manually presseddownwardly to insure that the adhesive on the lower face of the tape 58bonds firmly with the inner surface 22 of the cover sheet 24. At thesame time, the cable 50 should be positioned as seen in FIG. 6 so thatit extends out of the mold 60 when closed. Afterwards, the liquidurethane foam material 78 is poured into the mold to cover the heatingelement 16 as seen in FIGS. 7 and 8 so that the entire exposed portionof the heating element 16 is encapsulated within the liquid urethanefoam. This is followed by having the upper mold portion 62 pivoteddownwardly to close the mold 60 to cause the liquid foam material 78 toexpand and cure and form the foam core portion 20 of the seat cushionmember 12. The mold 60 is then opened, the cured article removed fromthe lower mold portion 64, and the extremities of the sheet 70 aretrimmed so as to provide the seat cushion member 12 seen in FIGS. 1 and2. Inasmuch as the carrier member 32 contains a multiplicity of opencells interconnected by thin web sections, the cured foam expands withinthe cells of the carrier member 32 and bonds to the inner face of thetape 58 in contact with the surface 36 of the carrier member 32. Thisresults in the foam filled carrier member 32 effectively becoming asolid spacer member with the resistance wire 38 permanentlysubstantially uniformly spaced from the inner surface 22 of the coversheet 24. As a consequence, there is no “reading” or outline of theheating element 16 and/or the resistance wire 38 in the outer surface ofthe cover sheet 24 of the seat cushion member 12.

[0028] A seat cushion 12 of the type described above was made using aheating element 16 in which the carrier member 32 was a reticulatedpolyurethane sheet purchased from New Dimension Industries, One StateStreet, Moonachie, N.J. 07074-1402. The carrier member 32 was of uniformthickness measuring approximately one quarter inch (the distance betweensurfaces 34 and 36) and was identified by New Dimension Industries as“NSV4 Charcoal 0.25×14×18”. The New Dimension Industries productspecification sheet identifies the carrier member 32 as “ReticulatedPolyurethane Ester Filter Foam S-04”. The specification sheet identifiesthe properties and values of such sheet as follows: PROPERTY VALUES CellCount 04 pores per inch + 1 Density 1.9 ± .1 lbs per cubic foot 25%Compression force deflection (CFD) 0.4 ± 1 lbs. per square inch Tensilestrength 16 lbs per square inch minimum Elongation 170% minimum TearStrength 4.5 lbs per square inch minimum Compression set @ 50%Deflection  15% loss maximum 25% CLD autoclave loss  10% maximumCompression set @ 50% Deflection  10% maximum autoclave loss Tensilestrength dry heat loss  15% maximum Volumetric air flow rate  21 ± 2cubic feet per minute

[0029] The resistance wire 38 that can be used with the heating element16 can be purchased from Springfield Wire Inc., 243 Cottage Street, Box638, Springfield, Mass. 01102-0638. and should have a resistance of 226plus-or-minus 5% Ohm/km with an operating temperature of −30 degreesCentigrade to plus 105 degrees Centigrade. The hot melt adhesive 54 usedfor holding the resistance wire 38 and the thermostat 56 in place on thecarrier member 32 was purchased from Hot Melt Technologies, Inc., 1723West Hamlin Road, P.O. Box 80067, Rochester, Mich. 48308 and wasidentified as Product Number 702. The adhesive 54 was applied with aspray gun so as to provide an open cell type bond with the webs of thecarrier member 32. The double-faced transfer tape 58 was made by CompacIndustries, Inc., Industrial Tape Division, 150 Fieldcrest Avenue,Edison, N.J. 08837. The tape 58 is a high tack acrylic adhesive tapecoated on both sides of a synthetic fiber netting serving as a scrimreinforcement and is supplied with a moisture stable liner 59 of 50 lbs.basis weight. The tape 58 is identified by Compac Industries, Inc. “NetBond 20”. Another tape that can be used successfully for bonding thecarrier member 32 to a seat cushion member cover sheet is made by theIndustrial Tape and Specialties Division of Minnesota Mining andManufacturing Company (3M) located at 3M Center Building 220-7E-01, St.Paul, Minn. 55144-1000. The 3M tape is identified as 950 Tape having anA-60 adhesive which is a medium firm acrylic pressure-sensitive adhesivesystem. The liner of the 3M tape is tan paper having an approximatethickness of 0.10 mm while the 3M tape only has a thickness of 0.13 mm.Another form of tape that can be used is a polyurethane film with anadhesive applied to opposed sides of the film. This form of tape wasmade experimentally by coating the opposed sides of the film withadhesives made by Adchem Corporation, 1852 Old Country Road, Riverhead,N.Y. 11901. The adhesive coating on one side of the film was identifiedas No. 5370 and the adhesive on the other side of the film wasidentified as No. 7332. The No. 5370 adhesive was applied to the sidewhich is intended to adhere to the inner surface of the cavity in themold. The thermostat 56 which forms a part of the heating element 16 waspurchased from Portage Electric Products, Inc., 7700 Freedom Ave. N.W.,North Canton, Ohio 44720. The thermostat 56 is identified by PortageElectric Products as Part No. C-102651, Model J and is a bi-metal snapaction thermostat.

[0030] At this juncture, it will be noted that it has been found thatwhen using a tape having a film or scrim as a reinforcement member, suchfilm or scrim should be flexible in the sense that it is capable ofbeing stretched sideways. This is important so that once the heatingelement 16 is embedded within the foam of the seat cushion member 12 andan occupant is seated in the seat assembly 10, the heating element 16substantially conforms in shape to the configuration of the buttocks ofthe occupant. In other words, the tape 58 along with the attachedcarrier member 32 can stretch, move laterally and downwardly togetherwith the foam material of the seat cushion member 12 when the weight ofthe occupant is applied by the buttocks of the occupant to the buttockssupport portion 18 of the seat cushion member 12. This provides asoftness to the buttocks support portion 18 permitting the buttocks ofthe seat occupant to have a comfortable seating effect without detectingany hardness in the support portion 18 of the seat cushion member 12.

[0031] Using a heating element 16 composed of the parts described above,the seat cushion member 12 was successfully made without any part of theheating element 16 being visible to an observer or outlined in thebuttocks support portion 18 of the seat cushion member 12. Moreover,when an occupant sits in the seat assembly 10, there is no feel of theresistance wires 38 or of the heating element 16 through the person'sbuttocks. During one successful molding operation of the type describedabove, rather than using the sheet 70 made of a vinyl material formaking the seat cushion member incorporating the heating element 16, afabric material backed with a plastic coating that rendered the fabricimpermeable to the foam was used. The fabric material was pre-formed toprovide the configuration of the seat cushion member, placed in a moldsuch as mold 60, and afterwards the heating element 16 was positioned inthe mold as described above. The liquid polyurethane foam material waspoured in the area of the heating element 16 making certain that theentire exposed portion of the heating element 16 is covered with theliquid foam material, the mold was closed, and the foam material wasallowed to cure to form the seat cushion member 12. The pre-formedfabric cover sheet used was made by Bayer Company located at Routes 5 &10, P.O. Box 186, South Deerfield, Mass. 01373. Such cover sheet wasidentified by Bayer Company as part PT 9611-Deerfield Urethane. The foammaterial used to make the core of the seat cushion was a polyurethanefoam having a density of 2.8 to 3 pounds per cubic foot.

[0032] In the above description of the present invention, the heatingelement 16 is shown as being incorporated only in the seat cushionmember 12 of the seat assembly 10. It should be apparent that theheating element 16 can equally as well be incorporated into the seatback member 14 and have the seat back member 14 formed utilizing aprocess such as described in connection with the seat cushion member 12.Also, the heating element 16 is shown and described as having thedouble-faced adhesive tape 58 bonded to the carrier member 32. By sodoing, the heating element 16 is a complete assembly ready for instantpositioning onto the inner surface 22 of the cover sheet. 24. It shouldbe apparent, however, that if desired, the double-faced adhesive tape 58could be a separate part of the carrier member 32 rather than have itinitially bonded, as seen in FIG. 5, to the lower surface 36 of thecarrier member 32. Under such circumstances, the tape 58, by itself,could be applied directly to the inner surface 22 in the buttockssupport section 18 of the cover sheet 24. After the tape is applied inthis manner, the liner 59 would be removed and the carrier 32, togetherwith the secured wire 38 and thermostat 56 would then be positioned ontothe tape 58 so as to cause the lower surface 36 of the carrier member 32to be bonded to the exposed adhesive face of the tape 58.

[0033] Various changes and modifications can be made in the constructionof the heating element and the method described above without departingfrom the spirit of the invention. For example, rather than utilizing anadhesive such as the hot melt adhesive for fixing the wire 38 to thecarrier member 32, other forms of adhesive have been found to work wellfor fixing the wire 38 to the carrier member 32, namely, Loctite Product2651 and 3M Product 6111HT. Both of these adhesives can also be appliedusing a spray gun. The important consideration is to have the adhesivedry relatively quickly and serve to join the wire 38 to the web portionsof the carrier member 32 in an open cell type bond which does notrestrict the flow of the liquid foam into the interior of the carriermember 16 during the molding of the seat cushion member 12. Also, thetape 58 does not necessarily need to be coextensive with the carriermember 32. Instead, wide strips of the tape 58 together with the liner59 can be applied to the surface 34 of the carrier member 32 along therows containing the zig-zag wire 38. Also, rather than using resistancewires, one could substitute electrically conductive pure carbon elementswhich could be secured to the upper surface 34 of the carrier member 32.Such changes and modifications are contemplated by the inventors andthey do not wish to be limited except by the scope of the appendedclaims.

What is claimed is:
 1. An electric heating element for an in-place foammolded seat assembly comprising a seat cushion member and a seat backmember each of which has a core portion made of a plastic foam materialbonded to an outer cover sheet, said heating element adapted to beencapsulated into one of said members and having a carrier membercomposed of a reticulated open cell flexible structure capable of beingfilled with said foam material during the molding process of said one ofsaid members, said carrier member having a pair of spaced surfaces, anelectric conductor secured to one of said surfaces, and a connectoradapted to join the other of said surfaces of said carrier member to theinner surface of said cover sheet to hold said carrier member on saidinner surface of said cover sheet so as to maintain said electricconductor spaced from and in a fixed position relative to said innersurface during the molding operation of said one of said members.
 2. Theelectric heating element of claim 1 wherein said electric conductor is awire provided with a pair of ends adapted to be electrically connectedto the electrical system of a vehicle.
 3. The electric heating elementof claim 1 wherein said electric conductor is a resistance wire arrangedin a zig-zag pattern to cover substantially the entire area of said oneof said surfaces.
 4. The electric heating element of claim 1 whereinsaid electric conductor is secured to said one of said surfaces of saidcarrier member by plastic welds.
 5. The electric heating element ofclaim 1 wherein said connector is a double-faced adhesive tape.
 6. Theelectric heating element of claim 1 wherein said connector is adouble-faced adhesive tape having a scrim as a reinforcement member. 7.The electric heating element of claim 3 wherein said wire is secured tothe webs of said carrier member by an adhesive.
 8. The electric heatingelement of claim 7 wherein said zig-zag pattern is provided in aplurality of substantially parallel rows.
 9. An electric heating elementfor an in-place foam molded seat cushion member having an integrallyformed outer cover, said heating element comprising a carrier memberhaving a flexible open-cell reticulated plastic structure adapted to befilled with liquid foam during the molding process, said carrier memberbeing provided with spaced and upper and lower substantially planarsurfaces, an electric conductor secured to said upper surface andcovering substantially the entire area of said upper surface, and anadhesive located on said lower surface of said carrier member adapted tobond said carrier member to the inner surface of said outer cover so asto maintain said electric conductor spaced from and in a fixed positionrelative to said inner surface during the molding operation of said seatcushion member.
 10. The electric heating element of claim 9 wherein saidelectric conductor is a wire provided with a pair of ends.
 11. Theelectric heating element of claim 9 wherein said double-faced adhesivetape is provided with scrim as a reinforcing member, and a paper lineron one face of said tape adapted to be removed prior to the heatingelement being incorporated into said seat cushion member.
 12. Theelectric heating element of claim 9 wherein said electric conductor issecured to said lower surface of said carrier member by a plurality ofplastic welds.
 13. The electric heating element of claim 8 wherein saidupper surface supports a thermostat for sensing the temperature of saidelectric heating element.
 14. The electric heating element of claim 13wherein said pair of ends of said conductor and said thermostat areelectrically connected through a cable to the electrical system of avehicle.
 15. The electric heater of claim 9 wherein said zig-zag patternis provided in a plurality of substantially parallel rows.
 16. A methodof making a heated seat member comprising the steps of: (a) pre-forminga cover sheet in the form of said seat member, (b) placing said coversheet into the cavity of a complementary mold, (c) providing an electricheating element comprising a carrier member formed as a reticulated opencell structure having a pair of spaced surfaces, one of said pair ofsurfaces supporting an electric conductor, (d) positioning said electricheating element in the buttocks support portion of said cover sheet withthe other of said pair of surfaces facing the inner surface of saidcover sheet so that said electric conductor is spaced from said innersurface, (e) connecting said other of said surfaces of said heatingelement to said inner surface of said cover sheet so as to maintain saidelectric heating element in a fixed position relative to said innersurface of said trim cover and have said electric conductor spaced fromsaid inner surface of said cover sheet, (f) pouring a liquid plasticfoaming material into said cavity of said mold so as to cause saidliquid plastic foaming material to enter the open cells of said carriermember and completely encapsulate the exposed portion of said heatingelement, and (g) closing the mold so as to cause said foaming materialto expand, be cured, and be bonded to said cover sheet within said moldso as to completely encapsulate said electric heating element withinsaid cured foaming material.
 17. The method of claim 16 wherein saidother of said surfaces is connected to said inner surface of said coversheet by an adhesive.
 18. The method of claim 16 wherein said other ofsaid surfaces is connected to said inner surface of said cover sheet bya double faced adhesive tape having a reinforcing scrim.
 19. The methodof claim 18 wherein said double-faced adhesive tape has one face thereofprovided with a paper liner and said liner is removed prior to said tapebeing connected to said inner surface of said cover sheet.
 20. Themethod of claim 16 wherein said conductor is a wire supported in azig-zag pattern on said one of said surfaces.